How to share a viewmodel between two or more Jetpack composables inside a Compose NavGraph?

You can to pass your top viewModelStoreOwner to each destination

1. directly passing to .viewModel() call, composable("first") in my example
2. overriding LocalViewModelStoreOwner for the whole content, so each composable inside CompositionLocalProvider will have access to the same view models, composable("second") in my example

val viewModelStoreOwner = checkNotNull(LocalViewModelStoreOwner.current) {
    "No ViewModelStoreOwner was provided via LocalViewModelStoreOwner"
}
val navController = rememberNavController()
NavHost(navController = navController, startDestination = "first") {
    composable("first") {
        val model = viewModel<SharedModel>(viewModelStoreOwner = viewModelStoreOwner)
    }
    composable("second") {
        CompositionLocalProvider(
            LocalViewModelStoreOwner provides viewModelStoreOwner
        ) {
            SecondScreen()
        }
    }
}

In the second case, you can get your model at any level of the composition tree, which is inside the CompositionLocalProvider:

@Composable
fun SecondScreen() {
    val model = viewModel<SharedModel>()
    SomeView()
}

@Composable
fun SomeView() {
    val model = viewModel<SharedModel>()
}